The aforesaid application discloses an apparatus for use on machines for winding webs of material, in particular plastic films, wherein by means of a separating element movable into the path of the web and extending over the width of the web the travelling web of material is separated from a rotatably driven winding core and reapplied to a new winding core.
In accordance with the invention described in the aforesaid application, when in the separating and applying position of the winding core, the working edge of the separating element is swingable in the feed direction of the web coaxially with respect to the winding core. It is possible by the use of such an arrangement and movement of the separating element to effect the separating operation satisfactorily, even at high winding speeds, and in fact this is so when separating plastic films and when using separating elements in the form of a saw which are often found to be effective for such films. The applying operation can also be carried out satisfactorily. The special advantage of the invention according to the aforesaid application lies in the fact that the winding speeds including the separating operations can be chosen to be so great that the winding speed can practically be suited to the delivery speed of the existing production machine. As a result, the working speed of the overall production can be substantially increased.
The requirement frequently arises, in the case of webs of material wound in their full width, and in particular in the case of films of plastic material, to cut or slit such webs longitudinally into individual webs of smaller width. It has been shown that by using the known arrangements wherein a cutting knife is moved transversely to the moving web of material, the production of such divided webs of material is not possible because, although a first portion of the web can be applied to the winding core during the separating operation, the remaining separated widths of the web fly loose, this being on account of the fact that an oblique cutting line results from the use of the known devices. Accordingly it has been the previous practice to use exclusively the so-called slitter rewinders, which have a separate longitudinal parting device. By this means the fully wound core is delivered over its full width to the slitter rewinder, at which point it is, in the course of a rewinding operation, subdivided by the longitudinal parting or slitting device. Subdivided widths of the web are then wound up on separate winders. Quite apart from the disadvantage of the fixed length of all the individual widths of material, a further quite substantial disadvantage of these rewinders is to be seen primarily in the additional capital expenditures for additional equipment and working, and above all in the fact that a separate expensive machine is necessary merely for separating the web into webs of smaller width.
The basic object of the present invention is, while employing the principles of the invention of the aforesaid application, to avoid these disadvantages and instead to provide an arrangement by the aid of which longitudinal separation of the web of material can be effected, and the winding of the individual webs carried out immediately following the production machine and directly upon the winding machine itself.